kubeadm-1m2w

Automated creation of kubeadm cluster (1 master, 2 workers) with OpenTofu and Ansible

What is this?

This automation stack provisions 3 Ubuntu 22.04 instances in the cloud provider of your choice (currently AWS and Alibaba Cloud are supported) each with 2 vCPUs, 8 GiB of memory, 16 GiB for the system disk (20 GiB with Alibaba Cloud) and an additional unpartitioned, unformatted 64GiB data disk, then installs a bare-bones Kubernetes cluster with kubeadm in a 3-node configuration with 1 master node and 2 worker nodes.

Disclaimer: This project is intended for educational and demonstration purposes and is not suitable for use in a production context. Use at your own risk.

Developing

Fork and clone this repository, then navigate to the project root and follow the instructions below.

Install pre-commit hook (optional)

The pre-commit hook runs formatting and sanity checks such as tofu fmt to reduce the chance of accidentally submitting badly formatted code that would fail CI.

ln -s ../../hooks/pre-commit ./.git/hooks/pre-commit

Prerequisites

AWS

If deploying the resources to AWS, you'll need to install and set up AWS CLI v2 with a valid access key and secret key corresponding to an IAM administrator account.

Alibaba Cloud

If deploying the resources to Alibaba Cloud, you'll need to set 2 environment variables prior to running OpenTofu:

export TF_VAR_aliyun_access_key="XXXXXXXXXXXXXXXXXXXXXXXX" # replace me!
export TF_VAR_aliyun_secret_key="XXXXXXXXXXXXXXXXXXXXXXXXXXXXXX" # replace me!

The access and secret keys should correspond to a RAM account with administrator privileges.

On-premises

If provisioning infrastructure manually on-premises either as VMs or on bare metal, skip the step for invoking OpenTofu.

However, you'll need to manually create two files which are otherwise created automatically by OpenTofu:

• ansible/ansible.cfg
• ansible/hosts.yaml

For reference, here's what both files look like - remember to adapt the values accordingly.

ansible.cfg

[defaults]
inventory = ./hosts.yaml
remote_user = ubuntu
private_key_file = /path/to/your/key.pem
host_key_checking = False

hosts.yaml

masters:
  hosts:
    master0:
      ansible_host: x.x.x.x
      private_ip: x.x.x.x
workers:
  hosts:
    worker0:
      ansible_host: x.x.x.x
    worker1:
      ansible_host: x.x.x.x

OpenTofu

Skip this step if manually provisioning the nodes on-premises either as VMs or on bare metal.

Install the latest version of OpenTofu. The version used is 1.6.0-rc1 at the time of writing (2023-12-22).

You'll also need an SSH key pair for remoting into your instances - generate this with ssh-keygen if you haven't already.

Ansible

Install the latest version of Ansible. The version used is 2.16.2 at the time of writing (2023-12-22).

Deploy

OpenTofu

Skip this step if manually provisioning the nodes on-premises either as VMs or on bare metal.

export CLOUD_PROVIDER="aws" # or "aliyun"
tofu -chdir="opentofu/${CLOUD_PROVIDER}/" init
tofu -chdir="opentofu/${CLOUD_PROVIDER}/" plan
tofu -chdir="opentofu/${CLOUD_PROVIDER}/" apply

The following OpenTofu variables are supported for AWS.

Variable	Type	Default	Description
profile	string	"default"	AWS profile to assume for AWS CLI v2 and OpenTofu
region	string	"ap-east-1"	AWS region to deploy the resources into
ssh_privkey_path	string	"~/.ssh/id_rsa"	Path to SSH private key. Evaluated with pathexpand() before use
ssh_pubkey_path	string	"~/.ssh/id_rsa.pub"	Path to SSH public key. Evaluated with pathexpand() before use
vpc_cidr	string	"10.0.0.0/16"	VPC CIDR block. Should be a valid RFC 1918 private subnet
subnet_cidr	string	"10.0.1.0/24"	Subnet CIDR block. Should be a valid subnet of the VPC CIDR block
instance_type	string	"t3.large"	EC2 instance type for each node
sys_volume_size	number	16	Size of root volume in GiB
data_volume_size	number	64	Size of EBS data volume in GiB

The following OpenTofu variables are supported for Alibaba Cloud.

Variable	Type	Default	Description
region	string	"cn-hongkong"	Alibaba Cloud region to deploy the resources into
vpc_cidr	string	"10.0.0.0/16"	VPC CIDR block. Should be a valid RFC 1918 private subnet
vswitch_cidr	string	"10.0.1.0/24"	vSwitch CIDR block. Should be a valid subnet of the VPC CIDR block
instance_type	string	"ecs.g7.large"	ECS instance type for each node
ssh_privkey_path	string	"~/.ssh/id_rsa"	Path to SSH private key. Evaluated with pathexpand() before use
ssh_pubkey_path	string	"~/.ssh/id_rsa.pub"	Path to SSH public key. Evaluated with pathexpand() before use
system_disk_size	number	20	Size of system disk in GiB
data_disk_size	number	64	Size of data disk in GiB

Ansible

export ANSIBLE_CONFIG="${PWD}/ansible/ansible.cfg"
ansible-playbook "${PWD}/ansible/playbook.yaml"

License

MIT